LibrePilot Forum

Users => Vehicles - MultiRotors => Topic started by: Parris on July 05, 2018, 12:05:24 am

Title: Flips and rolls . Fine tuning .
Post by: Parris on July 05, 2018, 12:05:24 am

LOS flying . ZMR 250 Thug .

Flips and rolls .

I'm very happy with the way this craft flies aggressively , and / or , passively . Depending on which Mode I'm set to . I have three Flight Mode settings . Progressively snappier from one to three .

My question :
     When I am in Mode 3 , Rattitude>Rattitude>AxisLock>CruiseControl , my craft hesitates , oscillates or bounces at around 10 degrees before coming back to level . I watch that in flight , and my automatic response is to just adjust my sticks .

     I can handle it . It's not a big problem when I'm in the open field flying . But , I don't always fly in an open field . I sometimes fly in a confined area . That's when it becomes tricky .

     Any suggestions ?


                                                                      Thanks ,

                                                                             Parris

Title: Re: Flips and rolls . Fine tuning .
Post by: TheOtherCliff on July 05, 2018, 01:04:01 am

Oscillation means your PI(D)s are too high.

You didn't mention whether you were using different PIDs for the different FMS positions.

I would consider enabling TPS in Stabilization->Advanced.

I have a similar Rattitude setup, and it helps a lot to simply release the stick sooner.

Title: Re: Flips and rolls . Fine tuning .
Post by: Parris on July 05, 2018, 01:23:01 am

   Thanks TheOtherCliff .

    I think my PID's are all about the same on each Flight Mode . I'll enable TPS on the snappier Flight Mode , ( 3 )  , and experiment with it .
    I just didn't want to upset all the other adjustments I had made in the other Flight Modes .

    Thanks a bunch ! I'll start working on that now . Run a few batteries . And, report later with my next issue .....lol.


                                                                       Thanks ,

                                                                              Parris

Title: Re: Flips and rolls . Fine tuning .
Post by: Parris on July 05, 2018, 02:15:56 am

Settings picture in attachment .

Title: Re: Flips and rolls . Fine tuning .
Post by: TheOtherCliff on July 05, 2018, 04:08:43 pm

Oh yea...  Oscillation can be caused by ESCs running a slow old protocol like PWM@50Hz which needs lower PIDs than the default ones.  If that is the case, instead of lowering PIDs, you should use a better ESC protocol/rate, at least PWM@490Hz or PWMSync.

Title: Re: Flips and rolls . Fine tuning .
Post by: Parris on July 05, 2018, 08:01:13 pm

I have Little Bee 20 amp ESC's . I've been flying this off and on for 2 years .

Output Configuration file attached .

Title: Re: Flips and rolls . Fine tuning .
Post by: f5soh on July 05, 2018, 09:00:01 pm

Your PID settings looks like just defaults.
Try lowering the Outer Loop Pterm from 2.5 to 2.0

You should do some tuning and lower a little bit the "P" term values on Rate/Inner loop.

Title: Re: Flips and rolls . Fine tuning .
Post by: Parris on July 06, 2018, 01:26:28 am

Thanks , f5soh . I'll try that adjustment . Waiting for the summer showers to end first .

Title: Re: Flips and rolls . Fine tuning .
Post by: hexamann02 on July 06, 2018, 11:23:18 pm

I have a kingkong 300 hex that has been a nightmare to get airborne. But, finally took flight today, but i noticed, it has a twitch, and shutters a little. PID's issue?



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Title: Re: Flips and rolls . Fine tuning .
Post by: TheOtherCliff on July 07, 2018, 06:57:43 am

PIDs are usually a regular oscillation.  Twitch and shudder sound different than that.  A video, best from on board, would help.